In cellular wireless systems, such as those using Long Term Evolution (LTE) and New Radio (NR) standards, resources for UL transmissions are normally scheduled by a network node (e.g., eNB or gNB). This can be done dynamically, for instance by an eNB scheduling an UL transmission per transmission time interval (TTI). Alternatively, this can be done using a semi persistent scheduling (SPS) framework, so that multiple TTIs are granted at the same time prior to a data transmission.
Configuration of SPS typically includes periodicity of the grant, allocation and modulation and coding scheme (MCS) in subsequent SPS occasions. Other types of grant-free transmissions can also be envisioned where some or all resources are granted semi-statically to a user equipment (UE), so that the UE can start transmitting over resources whenever needed without a need to ask for a dynamic grant.